The D. W. Parham et al. U.S. Pat. No. 4,320,876 granted on Mar. 23, 1982, discloses apparatus for selectively winding a plurality of strands of wire on a bobbin wherein each of the strands of wire travels through a hollow guide needle as the strand of wire is wound on the bobbin. The wire is temporarily wound onto a storage pin in order to avoid losing track of the end of the wire while the bobbin is being mounted onto a winding arbor. The disclosure of the abovementioned Parham et al. patent is incorporated herein by reference as though reproduced in full.
When the bobbin is firmly mounted to the arbor and suitably positioned, the wire guide needle is moved from the storage pin to a terminal pin molded into the bobbin structure. The terminal pin is preferably of square cross-section, having corners that bite into the surface of the wire wrapped around the terminal pin in accordance with the well-known wiring technology known as "wire-wrap". The wire issuing from the guide needle is then wrapped around the terminal pin so as to make good mechanical and electrical contact thereto. Following this, a breaker pin descends on a breaker mechanism and engages the wire stretched between the storage pin and the terminal pin. The wire breaks, preferably at a corner of the terminal pin where the corner has deeply indented the surface of the wire. However, it has been found through experience that the friction that exists between the breaker pin and the wire, as the breaker pin descends, may cause more tension to be applied to the portion of the wire that is stretched between the storage pin and the breaker pin than to the portion of the wire stretched between the breaker pin and the terminal pin. This is due to the angle usually assumed by the wire as it extends down from the storage pin to the terminal pin. The downward movement of the breaker pin thus tends to draw the wire frictionally from the storage pin toward the terminal pin.
The wire is then wound about the bobbin by rotating the arbor at a rapid rate while moving the wire guide needle in the axial direction of the arbor along the length of the coil bobbin so as to lay the wire evenly in precise layers on the bobbin. When the proper number of turns of wire has been wound onto the bobbin, the guide needle is moved to the proximity of another of the terminal pins; and wire is wrapped about that terminal pin by orbiting the wire guide needle. From this point, the wire guide needle moves toward the storage pin.
While the wire is being wound onto the bobbin, the coil of wire that was wound on the storage pin along with the length of wire that extends from the storage pin to the broken wire end is stripped from the storage pin and blown to a scrap bin by a blast of air. Therefore, the storage pin is again empty. The guide needle wraps the wire around the storage pin in order to retain control of the end of the wire after winding. The breaker pin again descends to break the wire, preferably at the terminal pin.
As further disclosed in the above-mentioned Parham et al. patent, the terminal pins on the bobbin are located at only one axial position along the arbor. It is undesirable, when winding wire on bobbins having terminal pins at two axial positions along the arbor axis, to pass the wire and the wire guiding needle through one set of terminal pins to reach another set of terminal pins. Besides, passing the wire over one set of terminal pins to reach the far set of terminal pins could cause undesirable breaking of the wire.